| Changes in carrying amount of goodwill |
The change in the carrying amount of goodwill for the six-month period ended June 30, 2026 is detailed as follows (in thousands): | | | | | | Six Months Ended June 30, 2026 | Goodwill balance at January 1 | | $ | 506,837 | Effect of foreign exchange | | | (514) | Additions and adjustments as the result of acquisitions | | | 36,377 | Disposals as the result of divestitures | | | (2,928) | Goodwill balance at June 30 | | $ | 539,772 |
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| Other intangible assets |
Other intangible assets at June 30, 2026 and December 31, 2025 consisted of the following (in thousands): | | | | | | | | | | | | June 30, 2026 | | | Gross Carrying | | Accumulated | | Net Carrying | | | Amount | | Amortization | | Amount | Patents | | $ | 34,575 | | $ | (15,428) | | $ | 19,147 | Distribution agreements | | | 3,250 | | | (3,106) | | | 144 | License agreements | | | 14,616 | | | (10,958) | | | 3,658 | Trademarks | | | 53,946 | | | (27,703) | | | 26,243 | Customer lists | | | 63,010 | | | (41,155) | | | 21,855 | Total | | $ | 169,397 | | $ | (98,350) | | $ | 71,047 |
| | | | | | | | | | | | December 31, 2025 | | | Gross Carrying | | Accumulated | | Net Carrying | | | Amount | | Amortization | | Amount | Patents | | $ | 33,979 | | $ | (14,760) | | $ | 19,219 | Distribution agreements | | | 3,250 | | | (3,069) | | | 181 | License agreements | | | 14,590 | | | (10,218) | | | 4,372 | Trademarks | | | 52,556 | | | (28,293) | | | 24,263 | Customer lists | | | 63,775 | | | (40,096) | | | 23,679 | Total | | $ | 168,150 | | $ | (96,436) | | $ | 71,714 |
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| Estimated amortization expense |
Estimated amortization expense for developed technology and other intangible assets for the next five years consisted of the following as of June 30, 2026 (in thousands): | | | | Year ending December 31, | | Estimated Amortization Expense | Remaining 2026 | | $ | 45,072 | 2027 | | | 88,683 | 2028 | | | 86,973 | 2029 | | | 77,270 | 2030 | | | 65,198 |
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